This invention relates to a method of manufacturing a milling cutter for the milling of so-called exotic materials such as titanium alloys, stainless steel, nimonic alloys etc, which are notoriously difficult to machine, and to a milling cutter per se.
The aerospace industry makes extensive use of titanium alloys etc, and, in common with other industries, continually seek to reduce costs of manufacture through either outsourcing to cheaper economies or increasing production.
Materials such as titanium, stainless and nimonic alloys are at the outer boundaries of milling capability and challenge current capabilities to improve productivity. Whilst grinding processes have been developed that have significantly improved productivity even in exotic materials, there are inevitably in some components features that are inaccessible to grinding wheels and hence cannot be shaped by grinding and which therefore still have to be machined.
In other, light duty, spheres of metal processing, fine tooth pitched cutters are known but are predominantly used for deburring applications, such cutters usually being disposable. These are generally open toleranced tools, the tooth style for a burr being a single ratchet tooth form. Although this produces an inherently weak tooth form (having a wedge angle of approximately 50°), it is of little consequence in deburring operations, but these generally very fine pitched cutters will not stand up to the rigours of machining operations such as milling, particularly of exotic material, with the capability and consistency demanded, nor lend themselves to re-sharpening for repeated use. Whilst it is well known that metal removal rate increases with the number of teeth on a cutter, there are of course limitations of how many teeth can be produced in a given cutting tool diameter as well as sharpening those teeth using conventional grinding techniques.